While the case could be appealed further to the U.S. Supreme Court, the upheld decision is a resounding victory for the First Amendment right of U.S. citizens to speak to and disagree with government officials in the social media era.

The main debate was whether the president's personal Twitter account was a public forum governed by the First Amendment. More traditional public forums are physical places owned by the government, such as sidewalks, parks and auditoriums. Peaceful public speech and demonstrations in those venues cannot be stopped based on what is being said without a compelling government interest. Twitter, however, is not a real-world space. And it's run by a private company.

Also key was the fact that the @realDonaldTrump account is used for governmental purposes. Specifically, the district court judge found that "the President presents the @realDonaldTrump account as being a presidential account as opposed to a personal account and, more importantly, uses the account to take actions that can be taken only by the President as President" – such as announcing the appointments and terminations of government officials.

The appeals court agreed on both points, saying, "the First Amendment does not permit a public official who utilizes a social media account for all manner of official purposes to exclude persons from an otherwise-open online dialogue because they expressed views with which the official disagrees."

This decision brings the Supreme Court's longstanding free speech doctrine into the social media era.

(Clay Calvert Brechner is Eminent Scholar in Mass Communication, at the University of Florida).